It has in certain countries.
What Twenty20 has done is showcase the fact that Cricket Grounds can be full. In most Twenty20 matches around the world, the attendances are full. In Test Cricket around the world, most stadiums are only half-full.
Clearly at this stage Twenty20 is more popular than Test Cricket!.
However does Test Cricket need to be revolutionized? I don't think so. In the late 70's after the "Packer Era" Cricket was at it's most popular point since the early days of W.G. ODI Cricket was starting to gather popularity but still Test Cricket was the main form of the game. Both Tests and ODI matches were being played to full houses of rowdy supporters. This was 30 years ago, however i believe Test Cricket can go back to being popular again.
In the late 70's they didn't need a Test Championship to make Tests popular. This was because Test Cricket was delightful show back then. Test matches involved fiery fast bowlers steaming in on fair pitches against the world's best batsmen. Test Cricket back then had DRAMA.
Drama is the key word for me. Tests in this era, don't have drama and that's why Test Cricket has lost it's popularity.
The recent series between the West Indies and England highlighted my point. 30 years ago, the public of West Indies would gather in any seat possible to watch there heroes take on the English or Aussies in a Test Match. In the recent series between the West Indies & England there were only a few 100 West Indians in the stadium.
The attendances have fallen because Test Cricket is predictable now. Around the world we see Test Matches played on placid pitches, a contest completely one-sided in the batsmen's favour. Too often we see Test Matches where both teams score 500 runs and the match turns into a draw.
Why does this happen? Money. Boards need the revenue in which 5 days Test Cricket gives. They are putting money over the fans enjoyment of the game.
However Test Cricket isn't completely lost yet. I'm from England and Test Cricket's popularity remains stronger than ever here. I went to a Test Match last year between England & South Africa and the Ground was packed for the whole day. England still loves Test Cricket and the reason i believe is because English pitches are FAIR.
In England pitches offer something for the bowlers and the batsmen! This means that the Test Matches won't be one-sided, and both teams have a chance. Test Cricket in England is rarely one-sided. Test Cricket here can capture the imagination of a public still. Remember 2005?
My last thought on this subject is that Twenty20 is not a bad omen for Test Cricket. Twenty20 can entertain pure Cricket fans and can reel in fans who may have not been interested in Cricket before Twenty20. These fans could then be converted into Test Cricket fans, if Test Cricket can remain interesting enough.
Lastly. I love Test Cricket. I always will. It seems like the attendances grow every year when England are playing Test Cricket, and more and more grounds around England want to host it.
However i enjoy watching Twenty20 too.